Transport refrigeration systems are commonly employed in connection with refrigerated transport trailers used in shipping perishable goods. The transport trailer is adapted to be connected to and towed by a truck tractor. The transport refrigeration system includes a refrigeration unit, an electric generator assembly and an engine for driving the electric generator, all supported on a framework structural support configured to be mounted to the front wall of the trailer.
In transport refrigeration systems, the refrigeration unit includes a condenser heat exchanger through which refrigerant is passed in heat exchange with ambient air as a cooling medium for condensing refrigerant from a vapor phase into a liquid phase. One or more, condenser fans are provided to draw the ambient air through the condenser heat exchanger. Typically, a pair of condenser fans are provided, disposed in a side-by-side arrangement.
In some transportation refrigeration system designs, such as for example the Vector 1800 transport refrigeration unit manufactured by Carrier Corporation, Farmington, Conn., U.S.A., a pair of condenser axial flow fans, disposed horizontally in side by side relationship, are mounted to the framework of the refrigeration system beneath and aft of the condenser heat exchanger and above the engine compartment wherein a diesel powered engine and electric generator driven by the engine are disposed. So configured, these axial flow fans direct substantially all of the air discharging from the condenser downwardly into and through the engine compartment to assist in the cooling the engine and generator. This air then exits through the bottom of the unit into the surrounding environment. However, this fan arrangement, coupled with the fact that substantially all of the condenser air exits through the bottom of the unit, can generate a relatively high level of noise.